Reaching the nonlinear regime of Raman amplification of ultrashort laser pulses

The intensity of a subpicosecond laser pulse was amplified by a factor of up to 1000 using the Raman backscatter interaction in a 2 mm long gas jet plasma. The process of Raman amplification reached the nonlinear regime, with the intensity of the amplified pulse exceeding that of the pump pulse by more than an order of magnitude. Features unique to the nonlinear regime such as gain saturation, bandwidth broadening, and pulse shortening were observed. Simulation and theory are in qualitative agreement with the measurements.     

Potential identity of multi-potential cancer stem-like subpopulation after radiation of cultured brain glioma

Background  

Glioblastoma multiforme (GBM) is the most frequently encountered brain cancer. Although the existence of cancer stem cells in GBM has been previously established, there is little evidence to explain the difference between cancer stem cells and radio-resistant cells in GBM. In an effort to increase our understanding of whether cellular radio-resistance is a characteristic associated with cancer stem cells, we developed a dissociated cell system of subpopulations derived from GBM, and demonstrated radiotherapy resistance therein.     

Thermal conductivity of geometrically frustrated, ferroelectric YMnO3: extraordinary spin-phonon interactions

The thermal conductivity of the magnetically frustrated, ferroelectric YMnO3 exhibits an isotropic suppression in the cooperative paramagnetic state, followed by a sudden increase upon magnetic ordering. This unprecedented behavior without an associated static structural distortion probably originates from the strong dynamic coupling between acoustic phonons and low-energy spin fluctuations in geometrically frustrated magnets. The replacement of magnetic Ho for Y at the ferroelectrically active site results in an even larger effect, suggestive of the strong influence of multiferroicity.     

Percolative Superconductivity in Mg1-xB2

Our results from various transport experiments on Mg1-xB2 indicate a surprising effect associated with the presence of a Mg deficiency in MgB2: the phase separation between Mg-vacancy rich and Mg-vacancy poor phases. The Mg-vacancy poor phase is superconducting, but the insulating nature of the Mg-vacancy rich phase probably originates from the Anderson (disorder-induced) localization of itinerant carriers. Furthermore, electron diffraction measurements indicate that within vacancy-rich regions these defects tend to order with intriguing patterns. This electronic phase separation in Mg1-xB2 shows similar, but also distinct characteristics compared with that observed in La(2)CuO(4+delta).     

Large transverse motion and micro-bunching of trapped electrons in a wakefield accelerator driven by temporally-asymmetric laser pulses

The transverse oscillatory motion of trapped electrons under the influence of the laser fields trailing the temporally-asymmetric driving laser pulse was investigated with a theoretical model of the quasi-steady state solution of trapped electron dynamics in the cavity. Our studies show that the transverse oscillation of electrons accelerated in the ion cavity can increase drastically due to the resonance with the laser field of the tail of the temporally-asymmetric pulse. The motion of the accelerated electrons can be represented by a forced harmonic oscillation and it was confirmed by 2D particle-in-cell simulations. These transverse oscillations of beams lead to micro-bunching as well, which can be used for generation of femtosecond coherent radiations of keV range photon energies.     

Giant charge relaxation resistance in the Anderson model

We investigate the dynamical charge response of the Anderson model viewed as a quantum RC circuit. Applying a low-energy effective Fermi liquid theory, a generalized Korringa-Shiba formula is derived at zero temperature, and the charge relaxation resistance is expressed solely in terms of static susceptibilities which are accessible by Bethe ansatz. We identify a giant charge relaxation resistance at intermediate magnetic fields related to the destruction of the Kondo singlet. The scaling properties of this peak are computed analytically in the Kondo regime. We also show that the resistance peak fades away at the particle-hole symmetric point.     

Asymptotic properties of a particular nonlinear regression quantile estimation

In this paper we shall be concerned with the asymptotic properties of the regression quantile estimation in the nonlinear regression time series models. For these, first we prove the strong consistency and derive the asymptotic normality of the regression quantile estimators for a particular sinusoidal regression model with a simple harmonic component. Next, we extend the results to more complicated sinusoidal models of several harmonic components.     

A simple HPLC method for the quantification of mizoribine in human serum: pharmacokinetic applications

A simple high-performance liquid chromatographic (HPLC) method was developed and validated for the quantification of mizoribine in human serum. After the addition of 70% perchloric acid and 3-methylxanthine (50 microg/mL, internal standard) to human serum, the samples were mixed and centrifuged at 12,000 rpm (1432 g) for 10 min. The supernatant was injected onto a C(18) column eluted with a mobile phase of 20 mm Na2HPO4 and methanol (93:7, v/v, pH 3) containing 0.04% octanesulfonic acid and detected utilizing an ultraviolet detector at 275 nm. The linear calibration curve was obtained in the concentration range of 0.1-4.0 microg/mL and the lower limit of quantification was 0.1 microg/mL. This method was validated with selectivity, linearity, precision and accuracy. In addition, the method was successfully applied to estimate the pharmacokinetic parameters of mizoribine in Korean subjects following an oral administration of 100 mg mizoribine (two Bredinine 50 mg tablets). The maximum serum concentration (C(max)) of 2.30 +/- 0.83 microg/mL was reached 2.27 +/- 0.66 h after an oral dose. The mean AUC(0-12 h) and the elimination half-life (t(1/2)) were 13.2 +/- 4.79 microg h/mL and 3.10 +/- 0.74 h, respectively.     

Ligand effects on luminescence of new type blue light-emitting mono(2-phenylpyridinato)iridium(III) complexes

Newly prepared hydrido iridium(III) complexes [Ir(ppy)(PPh3)2(H)L](0,+) (ppy = bidentate 2-phenylpyridinato anionic ligand; L = MeCN (1b), CO (1c), CN(-) (1d); H being trans to the nitrogen of ppy ligand) emit blue light at the emission lambda(max) (452-457, 483-487 nm) significantly shorter than those (468, 495 nm) of the chloro complex Ir(ppy)(PPh3)2(H)(Cl) (1a). Replacing ppy of 1a-d with F2ppy (2,4-difluoro-2-phenylpyridinato anion) and F2Meppy (2,4-difluoro-2-phenyl-m-methylpyridinato anion) brings further blue-shifts down to the emission lambda(max) at 439-441 and 465-467 nm with CIE color coordinates being x = 0.16 and y = 0.18-0.20 to display a deep-blue photoemission. No significant blue shift is observed by replacing PPh3 of 1a with PPh2Me to produce Ir(ppy)(PPh2Me)2(H)(Cl) (1aPPh 2Me), which displays emission lambda max at 467 and 494 nm. The chloro complexes, [Ir(ppy)(PPh3)2(Cl)(L)](0,+) (L = MeCN (2b), CO (2c), CN(-) (2d)) having a chlorine ligand trans to the nitrogen of ppy also emit deep-blue light at emission lambda(max) 452-457 and 482-487 nm.     

Structure and properties of Gd3Ge4: the orthorhombic RE3Ge4 structures revisited (RE = Y, Tb-Tm)

The new binary compound Gd(3)Ge(4) has been synthesized and its structure has been determined from single-crystal X-ray diffraction. Gd(3)Ge(4) crystallizes in the orthorhombic space group Cmcm (No. 63) with unit cell parameters a = 4.0953(11) A, b = 10.735(3) A, c = 14.335(4) A, and Z = 4. Its structure can be described as corrugated layers of germanium atoms with gadolinium atoms enclosed between them. The bonding arrangement in Gd(3)Ge(4) can also be derived from that of the known compound GdGe (CrB type) through cleavage of the (infinity)(1)[Ge(2)] zigzag chains in GdGe and a subsequent insertion of an extra germanium atom between the resulting triangular fragments. Formally, these characteristics represent isotypism with the Er(3)Ge(4) type (Pearson's oC28). However, re-examination of the crystallography in the whole RE(3)Ge(4) series (RE = Y, Tb-Tm) revealed discrepancies and called into question the accuracy of the originally determined structures. This necessitated a new rationalization of the bonding, which is provided in the context of a comparative discussion concerning both the original and revised structure models, along with an analysis of the trends across the series. The temperature dependence of the magnetic susceptibility of Gd(3)Ge(4) shows that it is paramagnetic at room temperature and undergoes antiferromagnetic ordering below 29 K. Magnetization, resistivity, and calorimetry data for several other members of the RE(3)Ge(4) family are presented as well.